Ongoing delays caused by avoidable late arrival of operating aircraft have a real cost, including crew duty problems, curfews and missed connection.
+1.
I guess a lot of this argument about whether you should always aim for maximum fuel saving might depend whether you are "networked" or not.
We are heavily encouraged (for fuel saving/cost/environmental/political reasons) to reduce burn, especially on the ground at base, but we also have an ops manual requirement to try arrive at the gate at base on time and changing the CI to try and achieve this is most certainly allowed (though doing so is most usually followed by the frustrations hinted at earlier).
One look at the list of transfer pax details on a typical Longhaul flight will show why - possibly 25% -50 % of pax will be connecting onto one of the company's short haul or long haul onwards flights. If you are late arriving, especially on an evening arrival, those pax are headed for hotels at company expense, followed by other complications for the company the next day. So if we depart a few minutes late downroute for whatever reason tweaking the CI by a few digits on a long haul sector to arrive at base on schedule makes more sense for the company (economically ) than blindly flying a CI that was planned in the office half a day ago.